Cosmetic Nanotechnology - American Chemical Society

Chapter 11

Nanotechnology and Applications in Cosmetics: General Overview

Downloaded by PENNSYLVANIA STATE UNIV on July 3, 2012 | http://pubs.acs.org Publication Date: April 12, 2007 | doi: 10.1021/bk-2007-0961.ch011

Linda M. Katz Office of Cosmetics and Colors, Center for Food Safety and Applied Nutrition, Food and Drug Administration, 5100 Paint Branch Parkway, HFS-100, College Park, M D 20740

Nanoparticles are defined as particles in the atomic, molecular or macromolecular levels ranging in size from 1-100 nanometers (nm); although for some novel properties the definition may be altered to take into account particles whose size may be 100 nm. As the commercial applications of nanotechnology have increased over the past several years, there has also been an increase in the potential uses of nanoparticles in cosmetic products as well as other products regulated by the Food and Drug Administration (FDA). There is a concern that substances considered safe for use as microparticles may penetrate more readily through skin as nanoparticles and exhibit different physical and chemical properties. The use of nanotechnology in cosmetics is not new, but dates back to 1961 with the advent of liposome technology use to market some moisturizing creams. This technology, which was used to alter optical properties, increase solubility and alter physical properties, provided for hydrophilic vesicles with phosphatidylcholine membrane(s) ranging in size from 15-3500 nm. The presentation below will address some of the current uses of nanotechnology in cosmetics marketed in the United States and the regulatory implications, as well as describe an F D A collaborative project with other Federal agencies and academia.

© 2007 American Chemical Society

In Cosmetic Nanotechnology; Morgan, S., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2007.

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The Regulatory Structure The mission of the Food and Drug Administration (FDA) is to ensure that drugs, medical devices, and vaccines are safe, effective, and properly labeled, and that food and cosmetic products are safe and properly labeled. The F D A paradigm for regulation of these products is based on a "risk management" framework that is applied on a product by product basis. However, some of the products that the F D A regulates, such as cosmetics and foods, do not require prior approval by F D A . The regulations stipulate that manufacturers of these products must ensure that they are safe prior to marketing. Cosmetics cover a wide variety of products including lipsticks, fragrances, hair dyes, body lotions, shampoos, and are defined in the Federal Food, Drug and Cosmetic Act F D & C Act) as (1) articles intended to be rubbed, poured, and sprinkled on, introduced into, or otherwise applied to the human body or any part thereof for cleansing, beautifying, promoting attractiveness, or altering the appearance, and (2) articles intended for use as a component of any such articles; except that such term shall not include soap. (1) Additional information on the regulation of cosmetics may be found at http://www.cfsan.fda.gov/~dms/costoc.html. The distinction between a cosmetic and a drug product may be confusing in some cases. Drugs are defined by their intended use in the F D & C Act as "(A) articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease... and (b) articles (other than food) intended to affect the structure or any function of the body of man or other animals.(Ref. 201(g)(1)). The intended use of a product is determined, for example, by evaluation of labeling claims, advertising matter, or oral or written statements by those (or their representatives)legally responsible for labeling. While sunscreens are regulated as drugs in the U.S. such a product containing a moisturizer is also a cosmetic. Similarly, toothpastes that contain fluoride or deodorants that are also antiperspirants are regulated as both drugs and cosmetics. Importantly for our discussion, the intended use of a product will determine its regulatory status, not the use of nanoparticles in the product's formulation.

Nanotechnology - Introduction F D A defines nanotechnology as the existence of materials or products at the atomic, molecular, or macromolecular levels, where at least one dimension affects the functional behavior of the drug/device and is in the length scale range of 1-100 nm. (2). To put this in perspective, 1 nm is equal to 10 hydrogen atoms laid side by side. The term "smart materials" (3) has been used to describe nanoparticles developed to target the delivery of drugs to specific organs of the body. Nanomaterials have many possible applications, including potential uses in cosmetic products, both in dry powders or liquid form. (4) The potential


195 benefits afforded these products include having the property of not scattering visible light but still having sufficient size to scatter U V light (5). These properties make nanoparticles of sunscreen ingredients (i.e. titanium dioxide) transparent to the eye but still able to block the absorption of U V light (5).


Nanoparticles Currently nanotechnology has been used in nanodispersed systems, nanocapsules, polymer systems and metal oxide nanoparticles. There are a variety of nanodispersed systems: liposomes, nanoemulsions, lipid nanoparticles; the solid core can be hydrophilic or hydrophobic depending upon the number of phospholid layers and deliver water or fat soluble actives. (Figure la, lb, l c , below) Nanoemulsions have been useful in typical cosmetic formulations, especially those found in skin and hair care preparations, because the light or oxygen sensitive ingredients can be protected and the emulsions have low biotoxicity.(6) Nanotechnology has been used in cosmetics since 1961 with the advent of liposome technology used to market some moisturizing creams. This technology, which was used to alter optical properties, increase solubility, and alter physical properties, provided for hydrophilic vesicles with phosphatidylcholine membrane (s) ranging in size from 15-3500 nm. (7) The additional advantage was no or low carrier biotixicity. (8) Most of the nanodispersions used in cosmetics still are lipophilic vesicles ranging in size from 50-200 nm. Products having nanoparticles in the range of 50-100 nm have been used to produce translucent lotions. In 2001, between $25-30 million was attributed to the U.S. consumption of particulate delivery systems, of which 30% was from nanoscale material. (9) Solid hydrophobic nanospheres, which have a high cationic charge density of the surface layer, tend to have strong interaction with skin/hair. The solid hydrophobic core protects water soluble and volatile ingredients. Examples of this use are found in "nutraceuticals", fragrances, and vitamins. Polymer nanoparticles can lead to a burst or controlled release of active ingredients and are considered to be to be more robust compared to liposomal formulations. They are found in a great number of naturally occurring and synthetic sources and are stable in both liquid and powder form.

Metal Oxide nanoparticles O f particular interest are the metal oxide nanoparticles, such as titanium dioxide ( T i 0 ) and zinc oxide (ZnO), that are found in many commercial 2



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Figure 1. Structure of nanodispersed systems. (Reproduced with permission from HAPPI March 2002. Copyright 2002.)



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Figure 2. Schematic Image of Nanosol


198 applications, including skin lotions and sunscreens because they alter U V absorption properties and appear to be clear or translucent on the skin. (5) Uncoated T i 0 absorbs photons of light and emits an excited electron. The electron can be transferred to 0 and absorbed into dermal layers; irradiation by sunlight can lead to oxidative damage. (10) Coating stops the formation of reactive species and prevents agglomeration of particles. The small crystal size and controlled particle size give excellent dispersibility, attractive skin feel and a transparency on the skin. (11) 2


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Current State of Activities The potential for toxicity from the use of nanoparticles has attracted special attention; for example, increasing the hydroxyl substitution decreases toxicity of buckyballs (12). Nanotubes which have potential application in aerospace, fuel cell, computer and electronic industries have been shown to cause pulmonary toxicity and have a potential inhalation threat. (13) Prolonged exposure to airborne carbon nanotubes in mouse studies has shown lesions and inflammation of the lung. (13) Federal initiatives are underway to address the new safety concerns that arise. Importantly for cosmetic applications, the extent to which nanoparticles can be absorbed into the skin is not yet clear. The Interagency Working Group on Nanotechnology Environmental and Health Implications (NEHI) was established by the Nanoscale Science, Engineering and Technology (NSET) subcommittee of the National Science and Technology Council (NSCT). The working group is comprised of individuals from a variety of agencies who have been tasked with looking at policies and issues that span the government and developing solutions to overcome these challenges. Federal agencies represented in N E H I include F D A , E P A , U S D A , NIOSH, OSHA, N I H and NSF. F D A collaborative projects include: (1) project with NIST that was begun in 2004, with the objective of developing expertise in nanotechnology in order to aid in the review of applications from sponsors of products that employ nanoparticles and to assist in writing guidance and setting standards for assays measuring biological responses. (2) Projects with NTP: 1 study is designed to examine the effect of nanoparticle size on skin penetration and the 2 study is to examine the ability of titanium dioxide and zinc oxide to penetrate excised human skin over 24 hours. In addition, the F D A has formed an InterCenter working group that meets quarterly to discuss the status of products formulated with nanoparticles, as well as regulatory issues and implications. Some of these issues include the regulation of combination products, regulation of categories of st

nd



199 products over which F D A has no premarket approval; and where in the product development nanotechnology may occur. At the present time, F D A is aware that several products under its jurisdiction employ nanotechnology, including a few cosmetic products that claim to contain nanoparticles to increase the stability or modify release of ingredients as well as the moisturizing creams, referred to above, that employ nanotechnology. Where do we go from here? We anticipate continued development and research in the area of nanotechnology and its use with encapsulation as well as new delivery systems to protect unstable ingredients,. However, as this technology continues to blossom we need to pay careful attention to toxicities that may develop.

References 1.

Federal Food, Drug, and Cosmetic Act, As Amended; Sec. 201, Washington, D.C. 1993; p. 4. 2. F D A Nanotechnology, www.fda.gov/nanotechnology/ 3. Lobenberg, Raimar, Smart Materials: Applications of Nanotechnology in Drug Delivery and Drug Targeting, IEEE, 82-83, July 2003. 4. Nanocapsules; Holster, P, et al; Technology White Papers; Cientifica; 10, October, 2003. 5. Dagani, R, Putting the 'nano' into composites, C & E News, 77, 25-37, June 7, 1999. 6. Lautenschlager, H . , Liposomes, in Handbook of Cosmetic Science and Technology (Eds. A . O . Barel, M. Payne and H.I. Maibach), Marcel Dekker, Inc, New York, 201-209, 2001. 7. Solid Lipid Nanoparticles: Production, Characterization and Applications; Mehnert, W, Mader, K ; Advanced Drug Delivery Reviews; 47, 165-196, 2001. 8. New York Society of Cosmetic Chemists Tech Notes, www.nyscc.org/nems/archieve/tech0402.htm 9. Vitamin Α-Loaded Solid Lipid Nanoparticles for Topical Use Drug Release Properties; Jenning V , Schafer-Korting M , Gohia S; Journal of Controlled Release, 66, 115-126, 2000. 10. Dunford, R., Salinaro, A , Cai, L . , Serpene, N . , Horikashi, S., Hidaka, H . , and Knowland, J., Chemical oxidation and D N A damage catalysed by inorganic sunscreen ingredients, FEBS Letters, 418, 87-90, 1997.


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11. Aromatics & More www.aromaticsandmore.com/products/vitamims_sunscreens.html 12. Oberdorster, E.,Manufactured nanomaterials (fiillerenes, C60) induce oxidative stress in the brain of juvenile large-mouth bass, Environ. Health Perspect. 112. 1058-1062, 2004 13. Lam, C - W , James, J.T., McCluskey, R., and Hunter, R . L . , Pulminary toxicity of single-wall carbon nanotubes in mice 7 and 90 days after intratracheal instillation, Tox. Sci, 77, 126-134, 2004


Cosmetic Nanotechnology - American Chemical Society

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